git adding with a submodule code example
Example 1: add submodule
$ git submodule add <remote_url> <destination_folder>
Example 2: git add submodule branch
git submodule add -b branch_name URL_to_Git_repo optional_directory_rename
$ git submodule add <remote_url> <destination_folder>
git submodule add -b branch_name URL_to_Git_repo optional_directory_rename